Weak toPoisonGhostSteel ×1.6

Attacker	Type	Moveset	DPS
Blacephalon	FireGhost	AstonishShadow Ball	79.4
Eternatus	PoisonDragon	Poison JabSludge Bomb	74.2
Metagross	SteelPsychic	Bullet PunchMeteor MashLegacy	72.8
Chandelure	GhostFire	HexShadow Ball	70.9
Tinkaton	FairySteel	Fairy WindGigaton HammerLegacy	70.8
Gengar	GhostPoison	LickShadow BallLegacy	70.8
Naganadel	PoisonDragon	Poison JabSludge Bomb	70.4
Dragapult	DragonGhost	AstonishShadow Ball	67.6
Lucario	FightingSteel	Bullet PunchMeteor Mash	67.2
Nihilego	RockPoison	Poison JabSludge Bomb	66.8
Hoopa	PsychicGhost	AstonishShadow Ball	66.4
Lunala	PsychicGhost	Shadow ClawShadow Ball	66.3

Fog boosts the Ghost attacks above. Overcast and Windy boost Ralts.

Level 40, 15 attack IV, costed against Ralts's own defense and typing, one per evolution family.

Ralts's moveset, CP and shiny All counters Raid board

Questions people ask

What is Ralts weak to in Pokémon GO?

Ralts takes 1.6 times from Poison, Ghost and Steel.

What's the best counter to Ralts?

Blacephalon with Astonish and Shadow Ball, worth 79.4 damage per second against Ralts's own defense. The full ranking is above.